Fig. 2.

Strategies for cell cocultures to replicate developmental processes. 2D cocultures are based on (A) direct and (B) indirect cocultures. Indirect cocultures can be performed by transwell culture systems (left) or by culturing a cell population with a conditioned medium used to previously culture the other cell population (right). 3D cocultures can be based on (C) scaffold-free approaches, such as hanging drop method (left) or ultra-low attachment cultures (right) or (D) scaffold-based approaches, including cell seeding on scaffolds (left) or cells embedding in scaffolds, typically hydrogel-based (right). Culture medium is represented in red; biomaterials/scaffolds are represented in blue.